People with dissociative personality disorders have two or more identities called sub personalities, each with a different definite set of memories, thoughts and behaviors. At a given time, one of the personalities is active. The transition from one personality to other is called switching and it can be random.
The relation between different identities may be mutually amnesic or mutually cognizant. If it is mutually amnesic, one personality is unaware of the other. In mutually cognizant relations, each sub-personality is aware of the other. They can talk to each other.
The Cause of the Disease
Researchers say that dissociative identity disorder is caused by repression: avoiding thoughts that cause pain and anxiety.
Repeated repression causes a person to pretend as a different person. The behavioral point of view says that a person develops dissociative disorder by dissociating himself from unwanted events.
State-dependant learning process is the process where, if a person learns something under some kind of arousal, tends to remember it strongly under the same kind of arousal. This may also be a reason for dissociative identity disorder, where a person behaves differently under different kinds of arousals.
Self hypnosis is yet another reason for this disorder. Some people may hypnotize themselves to forget unpleasant experiences. This becomes a habit and ultimately they do not know the difference between the reality and hypnosis.
Treating Dissociative Amnesia
Common methods for treating dissociative amnesia are drug therapy, hypnotic therapy and psychodynamic therapy. Psychodynamic therapists guide the person facing this problem to recall his forgotten memories. Hypnotic therapists also use hypnosis to enable their clients to recall their memories. Biologists use drugs such as sodium amobarbital or sodium pentobarbital to help the mind relax. This enables them to recall the anxiety producing memories. The last stage of these therapies is to integrate the different personalities into a single functional personality.